18.9.1 Common Signalling Principles

As the Information Age evolves, the amount of information that is transferred across networks continues to increase substantially and there will be much more focus on data communications. The IP technologies are a key part of this evolution. The structure, organisation and routing approaches used in telecommunications and IP networks are different. However, the signalling systems in the two forms of network have many principles in common. This chapter describes examples of IP signalling at each layer of the IP Model and draws a comparison with the telecommunications field.

18.9.2 IP Signalling Architecture

IP signalling uses a four-tier architecture consisting of an Application Layer, a Host-to-Host Layer, an Internet Layer and a Link Layer. There is a close relationship with the OSI Model and further work is needed to confirm alignment. The general alignment is:

• the IP Application Layer aligns with the Application, Presentation and Session Layers of the OSI Model;

• the Host-to-Host layer is aligned with the OSI Transport Layer;

• the Internet layer is aligned with the Network Layer;

• the Link Layer is aligned with the OSI Data-Link and Physical Layers.

18.9.3 The Address Resolution Protocol (ARP)

The Address Resolution Protocol (ARP) fits within the Link Layer of the IP Model. The ARP translates an IP address for an outgoing IP packet into the physical address of the destination point of the network. The address correlation is based on a table of translations. The table is populated by a procedure that broadcasts...